Heat exchanger

ABSTRACT

The present invention relates to a heat exchanger, which restricts a gap between a tube insertion hole formed on a header pipe for allowing both ends of a tube to inserted and combined thereto and the tube within a proper range, thereby making the manufacturing of the header pipes and the coupling of the tubes to the header pipe easy and preventing cracks and leak to improve durability.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger, and more particularly, to a heat exchanger, which restricts a gap between a tube insertion hole formed on a header pipe for allowing both ends of a tube to be inserted and combined thereto and the tube within a proper range, thereby making the manufacturing of the header pipes and the coupling of the tubes to the header pipe easy and preventing cracks and leak to improve durability.

2. Background Art

In general, a heat exchanger is installed on a flow channel of a heating and cooling system, and heats and cools a predetermined space by exchanging heat in such a way as to suck external heat through heat exchange medium flowing therein or emit heat to the outside.

Such a heat exchanger is manufactured in various forms according to its use purpose, for instance, a condenser and an evaporator using refrigerant as heat exchange medium, and a radiator and a heater core using cooling water as heat exchange medium.

Referring to FIGS. 1 and 2, the prior art heat exchanger will be described in brief as follows. As shown in the drawings, the heat exchanger 1 comprises: a pair of header pipes 10 spaced apart from each other laterally; a plurality of tubes 20, each of which both ends are combined to the header pipes 10 to connect the two header pipes 10 with each other; radiation fins 30 interposed between the tubes 20 for promoting a heat exchange by enlarging a heating surface area; and side supports 40 mounted at the outermost tubes 20 and radiation fins 30 for protecting the tubes 20 and the radiation fins 30.

Here, each header pipe 10 comprises a header 11 having a plurality of tube insertion holes 13 for mounting ends of the tubes 20 thereto, and a tank combined with the header 11 for forming a passageway to allow a flow of refrigerant.

The two header pipes 10 have baffles 60 formed alternately therein for allowing refrigerant to flow inside the tubes 20 in a zigzag form.

Such a heat exchanger 1 actively performs the heat exchange with the outside air during a process that refrigerant is introduced into the header pipes 10 through an inlet pipe 50 and flows inside the tubes 20 by the baffles 60 in the zigzag form, and then, discharges refrigerant through an outlet pipe 51.

Recently, a heat exchanger using carbon dioxide as refrigerant has been invented to prevent global warming. Carbon dioxide refrigerant has various merits, for instance, good compression efficiency and heat transmission.

Such a heat exchanger for carbon dioxide refrigerant is similar in structure with the previously described prior art heat exchanger 1, but has a structure to endure high pressure due to an operational property of carbon dioxide refrigerant.

Japanese Patent Laid-Open Publication No. 2003-314987 discloses a heat exchanger for carbon dioxide, which flows refrigerant through a communication passageway formed between a hole, which is formed on a side of a tube between the interior member and the exterior member, and a tank. In addition, Japanese Patent Laid-Open Publication No. 2003-172592 discloses a heat exchanger for carbon dioxide, which reduces a volume of a header by reducing a size of a hole of the interior member to be smaller than a width of a tube, thereby improving durability. Moreover, Japanese Patent Laid-Open Publication No. 2003-130584 discloses a heat exchanger for carbon dioxide that brazing material surrounds the outer periphery.

The prior art heat exchanger has the tube insertion holes formed on the header pipes to combine both ends of the tube thereto. However, the prior art heat exchangers have a problem in that it is weak in durability since a gap between the tube insertion hole and the tube is large.

In addition, the prior art heat exchanger having a structure that reinforcing member is bonded on the header pipes has a problem in that it is difficult to insert the tubes into the tube insertion holes since the tube insertion holes of the header pipes and the tube insertion holes of the reinforcing member are not coincided with each other.

If a gap between the tube insertion hole and the tube becomes greater to overcome the above problem, burst pressure is reduced, and hence the prior cracks and leak may be caused even at low pressure.

Therefore, there is a need to properly keep the gap between the tube insertion hole and the tube.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior arts, and it is an object of the present invention to provide a heat exchanger, which restricts a gap between a tube insertion hole formed on a header pipe for allowing both ends of a tube to be inserted and combined thereto and the tube within a proper range, thereby making the manufacturing of the header pipes and the coupling of the tubes to the header pipe easy and preventing cracks and leak to improve durability.

To accomplish the above objects, according to the present invention, there is provided a heat exchanger, which comprises: a plurality of tubes arranged in parallel with one another; header pipes, each having tube insertion holes for allowing both ends of each tube to be inserted thereto and combined to the header pipes, each header pipe being formed by a single member or by connecting plural members; a reinforcing member bonded on the outer periphery of each header pipe in such a way as to be positioned at the side of tube insertion hole; radiation fins interposed between the tubes; and inlet and outlet pipes formed on the header pipe for introducing and discharging heat exchange medium therethrough, wherein a gap (S) between the tube insertion hole and the tube satisfies the following formula to satisfy necessary durability and make the coupling of the tubes to the header pipes easy: 0.1 mm≦S≦2.5 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

FIG. 1 is a front view of a prior art heat exchanger;

FIG. 2 is a sectional view taken along the line of A-A of FIG. 1;

FIG. 3 is a partially enlarged perspective view of a heat exchanger according to the present invention, showing a state where tubes are combined to a header pipe on which a reinforcing member is bonded;

FIG. 4 is a sectional view taken along the line of B-B of FIG. 3;

FIG. 5 is a sectional view showing another structure of the reinforcing member of FIG. 4; and

FIG. 6 is a graph showing burst pressure to a gap between tube insertion hole and the tube of the heat exchanger according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will be now made in detail to the preferred embodiment of the present invention with reference to the attached drawings.

In the present invention, the same parts and structures as the prior art will have the same reference numerals as the prior art and description of the same parts and structures as the prior art will be omitted.

FIG. 3 is a partially enlarged perspective view of a heat exchanger according to the present invention, showing a state where tubes are combined to a header pipe on which a reinforcing member is bonded, FIG. 4 is a sectional view taken along the line of B-B of FIG. 3, FIG. 5 is a sectional view showing another structure of the reinforcing member of FIG. 4, and FIG. 6 is a graph showing burst pressure to a gap between tube insertion hole and the tube of the heat exchanger according to the present invention.

As shown in the drawings, the heat exchanger 100 according to the present invention comprises: a plurality of tubes 120 arranged in parallel with one another, each of the tubes having a flow channel of a predetermined form therein; a pair of header pipes 110 spaced apart from each other at a predetermined gap and arranged in parallel, each of the header pipes 110 having a passageway formed therein, both ends of each tube 120 being inserted and combined to the header pipes 110; radiation fins 120, each being interposed between the tubes 120 for promoting a heat exchange by enlarging a heating surface area; and inlet and outlet pipes 50 and 51 formed on the header pipe 110 for introducing and discharging heat exchange medium.

In addition, the heat exchanger according to the present invention further comprises: side supports 40 combined to the outermost tubes 120 and the outermost radiation fins 130 to reinforce the tubes 120 and the radiation fins 130; and a plurality of baffles 60 alternately mounted inside the header pipes 110 for inducing heat exchange medium introduced through the inlet pipe 50 to flow inside the tubes 120 in a zigzag form.

The inlet and outlet pipes 50 and 51 may be formed only on one header pipe 110, or the inlet pipe 50 may be formed on one header pipe 110 and the outlet pipe 51 may be formed on the other header pipe 110.

Meanwhile, the upper and lower ends of the header pipes 110 are sealed with end caps.

Moreover, each header pipe 110 has a plurality of tube insertion holes 110 formed at predetermined gaps in a longitudinal direction thereof for inserting and combining both ends of the tubes 120 thereto.

Here, the header pipes 110 may be formed by a single member or by connecting a plurality of members. That is, if the header pipe 110 is formed by connecting a plurality of the members, the header pipe 110 comprises a header member (not shown) having the tube insertion holes for inserting and combining the ends of the tubes 120 thereto and a tank member (not shown) combined to the header member to seal the header member and having a passageway.

Of course, the header pipe 110 may have one of various structures besides the above-mentioned structure.

Furthermore, the tube insertion hole 111 is larger than the tube 120 to make the coupling of the tubes 120 to the header pipes 110 easy and improve processability. On the other hand, if the tube insertion hole 111 becomes larger to improve processability, durability is deteriorated.

Therefore, in the present invention, a size of the tube insertion hole 111 is restricted to not only make the manufacturing of the header pipe 110 and the coupling of the tube 120 easy but also improve durability.

Particularly, burst pressure is deteriorated if the size of the tube insertion hole 111 becomes larger, but the tube 120 is damaged and leak is generated after brazing when the tube 120 is combined to the header pipe 110 when the size of the tube insertion hole 111 becomes smaller, and so, a yield rate is not good.

Therefore, in order to satisfy necessary durability and make the coupling of the tubes 120 to the header pipes 110 easy, it is preferable that a gap (S) between the tube insertion hole 111 and the tube 120 satisfies the following formula, 0.1 mm≦S≦2.5 mm.

FIG. 6 is a graph illustrating burst pressure to the gap between the tube insertion hole and the tube. Burst pressure has been performed at use temperature of 180° C., and P1 is burst pressure of a high pressure side (gas cooler) and P2 is burst pressure of a low pressure side (evaporator). As shown in the drawing, it is preferable that the high pressure side (gas cooler) has the gap (S) of 0.1 mm to 1.6 mm but the low pressure side (evaporator) has the gap (S) of 0.1 mm to 2.5 mm.

Here, in a heat exchange system using carbon dioxide as refrigerant, the gas cooler is called the high pressure side and the evaporator is called the low pressure side.

If the gap (S) between the tube insertion hole 111 and the tube 120 is less than 0.1 mm, the tube 120 is damaged when the tube 120 is combined to the header pipe 110, and it may cause leak after brazing. On the contrary, if the gap (S) between the tube insertion hole 111 and the tube 120 is larger than 1.6 mm (at the high pressure side) or 2.5 mm (at the low pressure side), burst pressure is reduced, and it causes deterioration of durability and cracks and leak even at a low pressure.

Additionally, a reinforcing member 115 is bonded on the outer periphery of the side of tube insertion hole of the header pipe 110 to improve strength and durability of the header pipe 110.

In this instance, also the reinforcing member 115 has tube insertion holes 115 a, and it is preferable that the tube insertion holes 115 a of the reinforcing member 115 is smaller than the tube insertion holes 111 of the header pipe 110.

In addition, as shown in FIG. 5, the reinforcing member 115 may have inserted portions 115 b bent toward the inside of the tube insertion holes 111 of the header pipe 110.

That is, the inserted portion 115 b is formed by bending the tube insertion hole 115 a of the reinforcing member 115 toward the inside of the tube insertion hole 111 of the header pipe 110.

When a thickness of the header pipe 110 is within a range of 0.5 mm to 6 mm, press working is good. In this instance, it is preferable that a thickness of the reinforcing member 115 is within a range of 0.5 mm to 3 mm and is smaller than or equal to the thickness of the header pipe 110. Moreover, a sectional area of the inside flow channel (C) of the header pipe 110 is within a range of 20 mm² to 500 mm².

Meanwhile, when the header pipes 110, the reinforcing members 115, the tubes 120 and the radiation fins 130 which are components of the heat exchanger 100 are temporarily assembled and brazed, a clad sheet (not shown) coated on the surface of each component is fused and bonded on each contact portion. In the above process, the clad sheet is fused into the gap between the tube insertion hole 111 and the tube 120 and bonds the header pipes 110 and the tubes 120 with each other.

As described above, the present invention describes the heat exchanger for carbon dioxide having improved durability by restricting the gap between the tube insertion hole 111 and the tube 120 within the range of 0.1 mm to 1.6 mm in case of the high pressure side (gas cooler) heat exchanger but within the range of 0.1 mm to 2.5 mm in case of the low pressure side (evaporator). However, the present invention can be applied to all heat exchangers without restriction to the above.

As described above, the present invention can make the manufacturing of the header pipes and the coupling of the tubes to the header pipes easy, and prevent cracks and leak to improve durability by restricting the gap between the tube insertion hole and the tube within a proper range.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. 

1. A heat exchanger comprising: a plurality of tubes arranged in parallel with one another; header pipes, each having tube insertion holes for allowing both ends of each tube to be inserted thereto and combined to the header pipes, each header pipe being formed by a single member or by connecting plural members; a reinforcing member bonded on the outer periphery of each header pipe in such a way as to be positioned at the side of tube insertion hole; radiation fins interposed between the tubes; and inlet and outlet pipes formed on the header pipe for introducing and discharging heat exchange medium therethrough, wherein a gap (S) between the tube insertion hole and the tube satisfies the following formula to satisfy necessary durability and make the coupling of the tubes to the header pipes easy: 0.1 mm≦S≦2.5 mm.
 2. The heat exchanger according to claim 1, wherein if the heat exchanger is a gas cooler, the gap (S) between the tube insertion hole and the tube satisfies the following formula: 0.1 mm≦S≦1.6 mm.
 3. The heat exchanger according to claim 1, wherein the reinforcing member has an inserted portion bent toward the inside of each tube insertion hole of the header pipe.
 4. The heat exchanger according to claim 1, wherein a thickness of the header pipe is within a range of 0.5 mm to 6 mm.
 5. The heat exchanger according to claim 1, wherein a thickness of the reinforcing member is within a range of 0.5 mm to 3 mm.
 6. The heat exchanger according to claim 1, wherein a sectional area of an inside flow channel of the header pipe is within a range of 20 mm² to 500 mm². 